MyCalqlator - Kotlin / Android Studio

#kotlin #android #beginners #calculator

Here we have my first Calculator in Android Studio

Start Layout

Suma

Resultado

Code backup

buttons_layouut.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">

    <GridLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:columnCount="4"
        android:rowCount="5">

        <Button
            android:id="@+id/button"
            android:layout_width="wrap_content"
            android:layout_height="100dp"
            android:layout_row="0"
            android:layout_column="0"
            android:layout_columnWeight="1"
            android:layout_margin="3dp"

            android:backgroundTint="#DCB3B3"
            android:onClick="borrar"
            android:text="CA"
            android:textColor="#5D0202"
            android:textSize="34sp"
            app:strokeColor="#5D0202"
            app:strokeWidth="2px" />

        <Button
            android:id="@+id/button2"
            android:layout_width="wrap_content"
            android:layout_height="100dp"
            android:layout_row="0"
            android:layout_column="1"
            android:layout_columnWeight="1"
            android:layout_margin="3dp"

            android:backgroundTint="#DCB3B3"
            android:onClick="borrar"
            android:text="C"
            android:textColor="#5D0202"
            android:textSize="34sp"
            app:strokeColor="#5D0202"
            app:strokeWidth="2px" />

        <Button
            android:id="@+id/button3"
            android:layout_width="wrap_content"
            android:layout_height="100dp"
            android:layout_row="0"
            android:layout_column="2"
            android:layout_columnWeight="1"
            android:layout_margin="3dp"

            android:backgroundTint="#DCB3B3"
            android:onClick="cambiarOperador"
            android:text="%"
            android:textColor="#5D0202"
            android:textSize="34sp"
            app:strokeColor="#5D0202"
            app:strokeWidth="2px" />

        <Button
            android:id="@+id/button4"
            android:layout_width="wrap_content"
            android:layout_height="100dp"
            android:layout_row="0"
            android:layout_column="3"
            android:layout_columnWeight="1"
            android:layout_margin="3dp"

            android:backgroundTint="#5D0202"
            android:onClick="cambiarOperador"
            android:text="÷"
            android:textSize="34sp" />

        <Button
            android:id="@+id/button5"
            android:layout_width="wrap_content"
            android:layout_height="100dp"
            android:layout_row="1"
            android:layout_column="0"
            android:layout_columnWeight="1"
            android:layout_margin="3dp"
            android:backgroundTint="@color/white"

            android:onClick="selectNumbers"
            android:text="7"
            android:textColor="#5D0202"
            android:textSize="34sp"
            app:strokeColor="#5D0202"
            app:strokeWidth="2dp" />

        <Button
            android:id="@+id/button6"
            android:layout_width="wrap_content"
            android:layout_height="100dp"
            android:layout_row="1"
            android:layout_column="1"
            android:layout_columnWeight="1"
            android:layout_margin="3dp"
            android:backgroundTint="@color/white"

            android:onClick="selectNumbers"
            android:text="8"
            android:textColor="#5D0202"
            android:textSize="34sp"
            app:strokeColor="#5D0202"
            app:strokeWidth="2dp" />

        <Button
            android:id="@+id/button7"
            android:layout_width="wrap_content"
            android:layout_height="100dp"
            android:layout_row="1"
            android:layout_column="2"
            android:layout_columnWeight="1"
            android:layout_margin="3dp"
            android:backgroundTint="@color/white"

            android:onClick="selectNumbers"
            android:text="9"
            android:textColor="#5D0202"
            android:textSize="34sp"
            app:strokeColor="#5D0202"
            app:strokeWidth="2dp" />

        <Button
            android:id="@+id/button8"
            android:layout_width="wrap_content"
            android:layout_height="100dp"
            android:layout_row="1"
            android:layout_column="3"
            android:layout_columnWeight="1"
            android:layout_margin="3dp"
            android:backgroundTint="#5D0202"

            android:onClick="cambiarOperador"
            android:text="x"
            android:textColor="@color/white"
            android:textSize="34sp"
            app:strokeColor="#5D0202"
            app:strokeWidth="2dp" />

        <Button
            android:id="@+id/button9"
            android:layout_width="wrap_content"
            android:layout_height="100dp"
            android:layout_row="2"
            android:layout_column="0"
            android:layout_columnWeight="1"
            android:layout_margin="3dp"
            android:backgroundTint="@color/white"

            android:onClick="selectNumbers"
            android:text="4"
            android:textColor="#5D0202"
            android:textSize="34sp"
            app:strokeColor="#5D0202"
            app:strokeWidth="2dp" />

        <Button
            android:id="@+id/button10"
            android:layout_width="wrap_content"
            android:layout_height="100dp"
            android:layout_row="2"
            android:layout_column="1"
            android:layout_columnWeight="1"
            android:layout_margin="3dp"
            android:backgroundTint="@color/white"

            android:onClick="selectNumbers"
            android:text="5"
            android:textColor="#5D0202"
            android:textSize="34sp"
            app:strokeColor="#5D0202"
            app:strokeWidth="2dp" />

        <Button
            android:id="@+id/button11"
            android:layout_width="wrap_content"
            android:layout_height="100dp"
            android:layout_row="2"
            android:layout_column="2"
            android:layout_columnWeight="1"
            android:layout_margin="3dp"
            android:backgroundTint="@color/white"

            android:onClick="selectNumbers"
            android:text="6"
            android:textColor="#5D0202"
            android:textSize="34sp"
            app:strokeColor="#5D0202"
            app:strokeWidth="2dp" />

        <Button
            android:id="@+id/button12"
            android:layout_width="wrap_content"
            android:layout_height="100dp"
            android:layout_row="2"
            android:layout_column="3"
            android:layout_columnWeight="1"
            android:layout_margin="3dp"
            android:backgroundTint="#5D0202"

            android:onClick="cambiarOperador"
            android:text="-"
            android:textColor="@color/white"
            android:textSize="34sp"
            app:strokeColor="#5D0202"
            app:strokeWidth="2dp" />

        <Button
            android:id="@+id/button13"
            android:layout_width="wrap_content"
            android:layout_height="100dp"
            android:layout_row="3"
            android:layout_column="0"
            android:layout_columnWeight="1"
            android:layout_margin="3dp"
            android:backgroundTint="@color/white"

            android:onClick="selectNumbers"
            android:text="1"
            android:textColor="#5D0202"
            android:textSize="34sp"
            app:strokeColor="#5D0202"
            app:strokeWidth="2dp" />

        <Button
            android:id="@+id/button14"
            android:layout_width="wrap_content"
            android:layout_height="100dp"
            android:layout_row="3"
            android:layout_column="1"
            android:layout_columnWeight="1"
            android:layout_margin="3dp"
            android:backgroundTint="@color/white"

            android:onClick="selectNumbers"
            android:text="2"
            android:textColor="#5D0202"
            android:textSize="34sp"
            app:strokeColor="#5D0202"
            app:strokeWidth="2dp" />

        <Button
            android:id="@+id/button15"
            android:layout_width="wrap_content"
            android:layout_height="100dp"
            android:layout_row="3"
            android:layout_column="2"
            android:layout_columnWeight="1"
            android:layout_margin="3dp"
            android:backgroundTint="@color/white"

            android:onClick="selectNumbers"
            android:text="3"
            android:textColor="#5D0202"
            android:textSize="34sp"
            app:strokeColor="#5D0202"
            app:strokeWidth="2dp" />

        <Button
            android:id="@+id/button16"
            android:layout_width="wrap_content"
            android:layout_height="100dp"
            android:layout_row="3"
            android:layout_column="3"
            android:layout_columnWeight="1"
            android:layout_margin="3dp"
            android:backgroundTint="#5D0202"

            android:onClick="cambiarOperador"
            android:text="+"
            android:textColor="@color/white"
            android:textSize="34sp"
            app:strokeColor="#5D0202"
            app:strokeWidth="2dp" />

        <Button
            android:id="@+id/button17"
            android:layout_width="wrap_content"
            android:layout_height="100dp"
            android:layout_row="4"
            android:layout_column="0"
            android:layout_columnSpan="2"
            android:layout_columnWeight="1"
            android:layout_margin="3dp"

            android:backgroundTint="@color/white"
            android:onClick="selectNumbers"
            android:text="0"
            android:textAlignment="viewStart"
            android:textColor="#5D0202"
            android:textSize="34sp"
            app:strokeColor="#5D0202"
            app:strokeWidth="2dp" />

        <Button
            android:id="@+id/button18"
            android:layout_width="wrap_content"
            android:layout_height="100dp"
            android:layout_row="4"
            android:layout_column="2"
            android:layout_columnWeight="1"
            android:layout_margin="3dp"
            android:backgroundTint="@color/white"

            android:onClick="selectNumbers"
            android:text="."
            android:textColor="#5D0202"
            android:textSize="34sp"
            app:strokeColor="#5D0202"
            app:strokeWidth="2dp" />

        <Button
            android:id="@+id/button20"
            android:layout_width="wrap_content"
            android:layout_height="100dp"
            android:layout_row="4"
            android:layout_column="3"
            android:layout_columnWeight="1"
            android:layout_margin="3dp"

            android:backgroundTint="#5D0202"
            android:onClick="igual"
            android:text="="
            android:textColor="@color/white"
            android:textSize="34sp"
            app:strokeColor="#5D0202"
            app:strokeWidth="2dp" />

    </GridLayout>
</LinearLayout>

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/txtTemp"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:padding="10dp"
        android:textAlignment="textEnd"
        android:textColor="#7B090000"
        android:textSize="34dp" />

    <TextView
        android:id="@+id/txtResult"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:padding="10dp"
        android:textAlignment="textEnd"
        android:textSize="60sp" />

    <include
        layout="@layout/buttons_layout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
</LinearLayout>

MainActivity.kt

package com.example.mycalqlator

import android.icu.text.DecimalFormat
import android.os.Bundle
import android.view.View
import android.widget.Button
import android.widget.TextView
import androidx.activity.enableEdgeToEdge
import androidx.appcompat.app.AppCompatActivity
import androidx.core.view.ViewCompat
import androidx.core.view.WindowInsetsCompat

class MainActivity : AppCompatActivity() {

    val SUMA = "+"
    val RESTA = "-"
    val MULTIPLICACION = "*"
    val DIVISION = "/"
    val PORCENTAJE = "%"

    var OpActual = ""

    var primerNumero:Double = Double.NaN
    var segundoNumero:Double = Double.NaN

    lateinit var txtTemp:TextView
    lateinit var txtResult:TextView

    lateinit var formatoDecimal: DecimalFormat

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        enableEdgeToEdge()
        setContentView(R.layout.activity_main)
        ViewCompat.setOnApplyWindowInsetsListener(findViewById(R.id.main)) { v, insets ->
            val systemBars = insets.getInsets(WindowInsetsCompat.Type.systemBars())
            v.setPadding(systemBars.left, systemBars.top, systemBars.right, systemBars.bottom)
            insets
        }

        formatoDecimal = DecimalFormat("#.#########")
        txtTemp = findViewById(R.id.txtTemp)
        txtResult = findViewById(R.id.txtResult)
    }

    fun cambiarOperador(b: View){
        if(txtTemp.text.isNotEmpty() || primerNumero.toString()!="NaN") {
            calqlar()
            val boton: Button = b as Button
            if (boton.text.toString().trim() == "÷") {
                OpActual = "/"
            } else if (boton.text.toString().trim() == "x") {
                OpActual = "*"
            } else {
                OpActual = boton.text.toString().trim()
            }
            txtResult.text = formatoDecimal.format(primerNumero) + OpActual
            txtTemp.text = ""
        }
    }

    fun calqlar(){
        try {
            if (primerNumero.toString() != "NaN") {
                if (txtTemp.text.toString().isEmpty()) {
                    txtTemp.text = txtResult.text.toString()
                }
                segundoNumero = txtTemp.text.toString().toDouble()
                txtTemp.text = ""

                when (OpActual) {
                    "+" -> primerNumero = (primerNumero + segundoNumero)
                    "-" -> primerNumero = (primerNumero - segundoNumero)
                    "*" -> primerNumero = (primerNumero * segundoNumero)
                    "/" -> primerNumero = (primerNumero / segundoNumero)
                    "%" -> primerNumero = (primerNumero % segundoNumero)
                }
            } else {
                primerNumero = txtTemp.text.toString().toDouble()
            }
        }catch (e:Exception){

        }
    }

    fun selectNumbers(b: View) {
        val boton: Button = b as Button
        val buttonText = boton.text.toString()
        val currentText = txtTemp.text.toString()

        when {
            buttonText == "." -> {
                if (currentText.contains(".")) return
                txtTemp.text = if (currentText.isEmpty()) "0." else currentText + "."
            }
            currentText == "0" -> {
                if (buttonText != "0") {
                    txtTemp.text = buttonText
                }
            }
            else -> {
                txtTemp.text = currentText + buttonText
            }
        }
    }


    fun igual(b: View){
        calqlar()
        txtResult.text = formatoDecimal.format(primerNumero)
        OpActual = ""
    }

    fun borrar(b:View){
        val boton:Button = b as Button
        if(boton.text.toString().trim()=="C"){
            if(txtTemp.text.toString().isNotEmpty()){
                var datosActuales:CharSequence = txtTemp.text as CharSequence
                txtTemp.text = datosActuales.subSequence(0, datosActuales.length - 1)

            }else{
                primerNumero = Double.NaN
                segundoNumero = Double.NaN
                txtTemp.text = ""
                txtResult.text = ""
            }
        }else if(boton.text.toString().trim() == "CA"){
            primerNumero = Double.NaN
            segundoNumero = Double.NaN
            txtTemp.text = ""
            txtResult.text = ""
        }
    }
}

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